The use of vibration damping devices based on the principle of resonators included in the device are known in the art. They are used for damping vibrations generated in structures or bodies, either still or in motion, when subject to impulses or forces that cause vibrations.
A damping device which uses resonators as active dynamic absorbers is disclosed in U.S. Pat. No. 5,431,261 where a structure with a large mass is damped by coupling thereto a damping member of smaller mass and continuously monitoring the frequency of excitation of the structure produced by applied load and the displacement of the damping member. The monitored frequency of excitation and displacement of the damping member are processed together with data relative to the mass, stiffness and damping characteristic of the damping member. A signal is outputted to produce a force acting on the damping member proportional to the displacement of the damping member with a controlled time delay to produce a frequency of vibration in the damping member substantially equal to the monitored frequency of excitation of the structure, this produces resonance of the damping member substantially at the monitored frequency of excitation and is effective to damp substantially the vibrations of the structure at the monitored frequency of excitation. The output signal is variable to produce resonance of the damping member variable over a range of frequencies including the natural frequency of vibration of the structure.
The results achieved by means of this damping device are not satisfactory. The harmonic response of the global system after an impulse follows a curve which reaches the desired level after too long a time.
In order to improve the damping efficiency of the damping device to bring it to a level satisfactory for engineering applications, solutions are known which provide for utilisation of damping means using viscosity effects, either alone or in addition to active dampers. However, in order to achieve a rapid damping effect such devices are too heavy, which is not always acceptable in many application, e.g. on spatial or flying vehicles.